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1.
The possibility of using biomass volume (= mean biomass present in the pond.week –1) to predict the total amount of harvestable cysts (= kg wet weight collected. week –1) produced in a culture pond by an Artemia franciscana population using a mixed model regression was evaluated for two different sampling methods; horizontal transects and vertical point samples. For transects, the following equation was found: `log (0.01 + cyst yields) = –2.05 + 0.025*(biomass volume)' with F
(1, 4.87) = 8.83 and p = 0.032. For the point samples, the regression was also significant with F
(1, 55.2) = 13.62 and p = 0.0005 for following equation: `log (0.01 + cyst yield) = –3.613 + 0.021*(biomass volume). As pond effect and interaction terms did not significantly explain a significant portion of the variance for either of the sampling methods (Transects: pond: F
(3, 14.3) = 2.48; p = 0.103; pond*biomass volume: F
(3, 3.61) = 4.63; p = 0.0976; Point samples: pond: F
(3, 44.5) = 0.00; p = 0.999; pond*biomass volume: F
(3, 44.2) = 0.11; p = 0.954 ), the variable pond (repeated measurement factor) was not included in the final calculations for the regression equations. Although a combination of factors influences the equation, the high significance levels of the regression indicate biomass volume can be safely used to predict production trends. The low investment requirements of this method make it especially attractive for on farm use, where correctly determining the point of cyst decline will help farmers to allocate resources where needed. 相似文献
2.
Junfeng Qu Youjian Liang Shuhong Xu Rong Zhang Changgui Lu Chunlei Wang Yiping Cui 《Luminescence》2022,37(5):777-783
During the fabrication of lateral-structured photodetectors based on CH3NH3PbI3 film, antisolvents represented by toluene are usually used to accelerate the crystallization of perovskite. Using antisolvent not only leads to the formation of shrinkage holes at the bottom of the perovskite layer, but the toxicity of antisolvents would also hinder the industrial preparation of perovskite devices. An antisolvent-free method is a possible solution to avoid these problems. Here, we report a lateral-structured photodetector based on an antisolvent-free method. The lateral photodetector exhibited a high responsivity of 1.75 A⋅W−1 and specific detectivity (D*) of 3.54 × 1012 Jones. In particular, the results indicated that the solvent had an influence on perovskite film morphology, crystallization, and device performance. The prepared CH3NH3PbI3 film presented needle-like crystals and low performance with single precursor solvent N,N-dimethylformamide (DMF). In comparison, appropriate mixing of dimethyl sulfoxide (DMSO) could improve the morphology, crystallization, and performance of the film. In addition, the solvent volume ratio of the precursor had a profound effect on the performance of the as-prepared photodetectors. At a DMSO:DMF volume ratio of 5:5, the as-prepared film had massive perovskite crystals and fewer defects, resulting in optimal device performance, which can be explained by Urbach energy. 相似文献
3.
Hande Bas Ayata Metin Güden Cemile Ceylan Nadir Kücük Kayihan Engin 《Reports of Practical Oncology and Radiotherapy》2011,16(3):95-102
Aim
Our aim was to improve dose distribution to the left breast and to determine the dose received by the ipsilateral lung, heart, contralateral lung and contralateral breast during primary left-sided breast irradiation by using intensity modulated radiotherapy (IMRT) techniques compared to conventional tangential techniques (CTT). At the same time, different beams of IMRT plans were compared to each other in respect to CI, HI and organs at risk (OAR) dose.Background
Conventional early breast cancer treatment consists of lumpectomy followed by whole breast radiation therapy. CTT is a traditional method used for whole breast radiotherapy and includes standard wedged tangents (two opposed wedged tangential photon beams). The IMRT technique has been widely used for many treatment sites, allowing both improved sparing of normal tissues and more conformal dose distributions. IMRT is a new technique for whole breast radiotherapy. IMRT is used to improve conformity and homogeneity and used to reduce OAR doses.Materials and methods
Thirty patients with left-sided breast carcinoma were treated between 2005 and 2008 using 6, 18 or mixed 6/18 MV photons for primary breast irradiation following breast conserving surgery (BCS). The clinical target volume [CTV] was contoured as a target volume and the contralateral breast, ipsilateral lung, contralateral lung and heart tissues as organs at risk (OAR). IMRT with seven beams (IMRT7), nine beams (IMRT9) and 11 beams (IMRT11) plans were developed and compared with CTT and among each other. The conformity index (CI), homogeneity index (HI), and doses to OAR were compared to each other.Results
All of IMRT plans significantly improved CI (CTT: 0.76; IMRT7: 0.84; IMRT9: 0.84; IMRT11: 0.85), HI (CTT: 1.16; IMRT7: 1.12; IMRT9: 1.11; IMRT11: 1.11), volume of the ipsilateral lung receiving more than 20 Gy (>V20 Gy) (CTT: 14.6; IMRT7: 9.08; IMRT9: 8.10; IMRT11: 8.60), and volume of the heart receiving more than 30 Gy (>V30 Gy) (CTT: 6.7; IMRT7: 4.04; IMRT9: 2.80; IMRT11: 2.98) compared to CTT. All IMRT plans were found to significantly decrease >V20 Gy and >V30 Gy volumes compared to conformal plans. But IMRT plans increased the volume of OAR receiving low dose radiotherapy: volume of contralateral lung receiving 5 and 10 Gy (CTT: 0.0–0.0; IMRT7: 19.0–0.7; IMRT9: 17.2–0.66; IMRT11: 18.7–0.58, respectively) and volume of contralateral breast receiving 10 Gy (CTT: 0.03; IMRT7: 0.38; IMRT9: 0.60; IMRT11: 0.68). The differences among IMRT plans with increased number of beams were not statistically significant.Conclusion
IMRT significantly improved conformity and homogeneity index for plans. Heart and lung volumes receiving high doses were decreased, but OAR receiving low doses was increased. 相似文献4.
Alex J Lomas George GQ Chen Alicia J El Haj Nicholas R Forsyth 《World journal of stem cells》2012,4(9):94-100
AIM: To establish the potential of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) as a material for tendon repair. METHODS: The biocompatibility of PHBHHx with both rat tenocytes (rT) and human mesenchymal stem cells (hMSC) was explored by monitoring adhesive characteristics on films of varying weight/volume ratios coupled to a culture atmosphere of either 21% O2 (air) or 2% O2 (physiological normoxia). The diameter and stiffness of PHBHHx films was established using optical coherence tomography and mechanical testing, respectively. RESULTS: Film thickness correlated directly with weight/volume PHBHHx (r2 = 0.9473) ranging from 0.1 mm (0.8% weight/volume) to 0.19 mm (2.4% weight/volume). Film stiffness on the other hand displayed a biphasic response which increased rapidly at values 1.6% weight/volume. Optimal cell attachment of rT required films of ≥ 1.6% and ≥ 2.0% weight/volume PHBHHx in 2% O2 and 21% O2 respectively. A qualitative adhesion increase was noted for hMSC in films ≥ 1.2% weight/volume, becoming significant at 2% weight/volume in 2% O2. An increase in cell adhesion was also noted with ≥ 2% weight/volume PHBHHx in 21% O2. Cell migration into films was not observed. CONCLUSION: This evaluation demonstrates that PHBHHx is a suitable polymer for future cell/polymer replacement strategies in tendon repair. 相似文献
5.
R. F. Grover M. A. Selland R. G. McCullough T. E. Dahms E. E. Wolfel G. E. Butterfield J. T. Reeves J. E. Greenleaf 《European journal of applied physiology and occupational physiology》1998,77(3):264-270
When humans ascend to high altitude (ALT) their plasma volume (PV) and total blood volume (BV) decrease during the first
few days. With continued residence over several weeks, the hypoxia-induced stimulation of erythropoietin increases red cell
production which tends to restore BV. Because hypoxia also activates the β-adrenergic system, which stimulates red blood cell
production, we investigated the effect of adrenergic β-receptor inhibition with propranolol on fluid volumes and the polycythemic
response in 11 healthy unacclimatized men (21–33 years old exposed to an ALT of 4300 m (barometric pressure 460 Torr) for
3 weeks on Pikes Peak, Colorado. PV was determined by the Evans blue dye method (PVEB), BV by the carbon monoxide method (BVCO), red cell volume (RCV) was calculated from hematocrit (Hct) and BVCO, and serum erythropoietin concentration ([EPO]) and reticulocyte count, were also determined. All determinations were made
at sea level and after 9–11 (ALT-10) and 19–20 (ALT-20) days at ALT. At sea level and ALT, six men received propranolol (pro,
240 mg · day−1), and five received a placebo (pla). Effective β-blockade did not modify the mean (SE) maximal values of [EPO] [pla: 24.9
(3.5) vs pro: 24.5 (1.5) mU · ml−1] or reticulocyte count [pla: 2.7 (0.7) vs pro: 2.2 (0.5)%]; nor changes in PVEB [pla: −15.8 (3.8) vs pro: −19.9 (2.8)%], RCVCO [pla: +7.0 (6.7) vs pro: +10.1 (6.1)%], or BVCO [pla: −7.3 (2.3) vs pro: −7.1 (3.9)%]. In the absence of weight loss, a redistribution of body water with no net loss is
implied. Hence, activation of the β-adrenergic system did not appear to affect the hypovolemic or polycythemic responses that
occurred during 3 weeks at 4300 m ALT in these subjects.
Accepted: 25 August 1997 相似文献
6.
Jorge Zagaceta Javier J. Zulueta Gorka Bastarrika Inmaculada Colina Ana B. Alcaide Arantza Campo Bartolome R. Celli Juan P. de Torres 《PloS one》2013,8(6)
Rationale
Epicardial Adipose Tissue (EAT) volume as determined by chest computed tomography (CT) is an independent marker of cardiovascular events in the general population. COPD patients have an increased risk of cardiovascular disease, however nothing is known about the EAT volume in this population.Objectives
To assess EAT volume in COPD and explore its association with clinical and physiological variables of disease severity.Methods
We measured EAT using low-dose CT in 171 stable COPD patients and 70 controls matched by age, smoking history and BMI. We determined blood pressure, cholesterol, glucose and HbA1c levels, microalbuminuria, lung function, BODE index, co-morbidity index and coronary artery calcium score (CAC). EAT volume were compared between groups. Uni and multivariate analyses explored the relationship between EAT volume and the COPD related variables.Results
COPD patients had a higher EAT volume [143.7 (P25–75, 108.3–196.6) vs 129.1 (P25–75, 91.3–170.8) cm3, p = 0.02)] and the EAT volume was significantly associated with CAC (r = 0.38, p<0.001) and CRP (r = 0.32, p<0.001) but not with microalbuminuria (r = 0.12, p = 0.13). In COPD patients, EAT volume was associated with: age, pack-years, BMI, gender, FEV1%, 6 MWD, MMRC and HTN. Multivariate analysis showed that only pack-years (B = 0.6, 95% CI: 0.5–1.3), BMI (B = 7.8, 95% CI: 5.7–9.9) and 6 MWD (B = −0.2, 95% CI: −0.3–−0.1), predicted EAT volume.Conclusions
EAT volume is increased in COPD patients and is independently associated with smoking history, BMI and exercise capacity, all modifiable risk factors of future cardiovascular events. EAT volume could be a non-invasive marker of COPD patients at high risk for future cardiovascular events. 相似文献7.
Yunlong Li Weihai Sun Weibo Yan Senyun Ye Haixia Rao Haitao Peng Ziran Zhao Zuqiang Bian Zhiwei Liu Huanping Zhou Chunhui Huang 《Liver Transplantation》2016,6(24)
In the present work, a Pb‐assisted two step method is successfully proposed to fabricate high‐quality CH3NH3Sn0.5Pb0.5I3 (MASn0.5Pb0.5I3) perovskite film on the indium tin oxide (ITO) glass/poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) substrate. The film shows regular crystalline grains with a flat and compact morphology as well as full coverage on the planar PEDOT:PSS substrate. Remarkably, corresponding devices ITO/PEDOT:PSS/MASn0.5Pb0.5I3/C60/2,9‐dimethyl‐4,7‐diphenyl‐1,10‐phenanthroline/Ag are fabricated with high reproducibility, achieving a high power conversion efficiency of 13.6%, which is, to the best of knowledge, the most efficient solar cell based on Sn‐based perovskite. 相似文献
8.
O. B. Nielsen 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1997,167(3):159-168
Adrenergic stimulation of trout red blood cells activates a Na+/H+-exchange. If unopposed, the ensuing increase in cell Na+ leads to an isosmotic cell swelling. In this study the effect of the level of haemoglobin O2 saturation on volume regulation has been investigated in adrenergically stimulated red blood cells from trout: at full haemoglobin
O2 saturation, net influx of Na+ through the Na+/H+-exchanger was balanced by net efflux of K+ and no increases in cell volume took place. In contrast, at low O2 saturation (8–14%) adrenergic stimulation led to a substantial increase in cell Na+, K+ and volume. Moreover, cell volume recovery after adrenergic swelling was incomplete at low O2 saturation, whereas cells at high O2 saturation exhibited a fast and complete cell volume recovery. In cells exposed to alternating high and low O2 saturation, volume regulation was similar to the regulation found in cells maintained at high O2 saturation. In cells at high O2 saturation, extrusion of cellular Na+ by the Na+/K+-pump significantly contributed to the volume decrease. It is concluded that trout red blood cells at high or alternating
O2 saturations possess a powerful regulatory volume decrease response that is shut off at low O2 saturation. The physiological implications of this regulation is discussed.
Accepted: 30 September 1996 相似文献
9.
Objective
Apparent diffusion coefficients (ADC) can help differentiate between central nervous system (CNS) lymphoma and Glioblastoma (GBM). However, overlap between ADCs for GBM and lymphoma have been reported because of various region of interest (ROI) methods. Our aim is to explore ROI method to provide the most reproducible results for differentiation.Materials and Methods
We studied 25 CNS lymphomas and 62 GBMs with three ROI methods: (1) ROI1, whole tumor volume; (2) ROI2, multiple ROIs; and (3) ROI3, a single ROI. Interobserver variability of two readers for each method was analyzed by intraclass correlation(ICC). ADCs were compared between GBM and lymphoma, using two-sample t-test. The discriminative ability was determined by ROC analysis.Results
ADCs from ROI1 showed most reproducible results (ICC >0.9). For ROI1, ADCmean for lymphoma showed significantly lower values than GBM (p = 0.03). The optimal cut-off value was 0.98×10−3 mm2/s with 85% sensitivity and 90% specificity. For ROI2, ADCmin for lymphoma was significantly lower than GBM (p = 0.02). The cut-off value was 0.69×10−3 mm2/s with 87% sensitivity and 88% specificity.Conclusion
ADC values were significantly dependent on ROI method. ADCs from the whole tumor volume had the most reproducible results. ADCmean from the whole tumor volume may aid in differentiating between lymphoma and GBM. However, multi-modal imaging approaches are recommended than ADC alone for differentiation. 相似文献10.
Tetsuharu Iwata Tsuyoshi Hirose Masaru Nakamura Masatoshi Yamaguchi 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1994,654(2)
A simple and highly sensitive high-performance liquid chromatographic method for the direct determination of urinary glucuronide conjugates is described. The method is based on the direct derivatization of the glucuronic acid moiety in glucuronide conjugates with 6,7-dimethoxy-1-methyl-2 (1 H)-quinoxalinone-3-propionylcarboxylic acid hydrazide. The derivatization reaction proceeds in aqueous solution in the presence of pyridine and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide at 0–37°C. The resulting fluorescent derivatives are separated on a C18 column using methanol—acetonitrile—0.5% triethylamine in water (1:1:2, v/v) as mobile phase, and are detected spectrofluorimetrically at 445 nm with excitation at 367 nm. The detection limits (signal-to-noise RATIO = 3) for the glucuronides are 13–48 fmol for an injection volume of 10 μl (130–480 fmol per 5 μl of human urine). The method was applied to the measurement of etiocholanorone-3-glucuronide and androsterone-3-glucuronide in human urine. The method is simple and rapid without conventional liquid—liquid extraction of the glucuronides from urine. 相似文献
11.
R. Vijayakumar S. Murdoch T. Deheny W.A.W. Walters 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1981,225(1):47-54
The development of a “bound—free” separation technique and its application to the radioimmunoassay of prostaglandin F2α is described. The method is simple, rapid, free of non-specific binding and could be performed either at 4°C or at room temperature. A total of 100 tubes could be subjected to “bound—free” separation in 30 min at 4°C. The bound fraction is collected directly into scintillation vials. The total column length was 9.5 cm, of which the bed volume was 2.5 ml. The PGF2α radioimmunoassay incubation volume of 0.3 ml when bedded in required 1.4 ml of elution buffer to elute the antibody-bound fraction. The free fraction was washed out with 4.0 ml of buffer and the columns were ready for further use. A standard curve of high sensitivity (5 pg) and good reproducibility (CV %: intra-assay = 6.54; inter-assay = 9.68) was obtained. 相似文献
12.
Nethika S. Suraweera Austin A. Albert Michael E. Peretich Joshua Abbott James R. Humble Craig E. Barnes 《Molecular simulation》2014,40(7-9):618-633
The adsorptive and diffusive behaviour of methane and carbon dioxide in amorphous nanoporous adsorbents composed of spherosilicate building blocks, in which isolated metal sites have been distributed, is examined. The adsorbent contains cubic silicate building blocks (spherosilicate units: Si8O20), which are cross linked by SiCl2O2 bridges and decorated with either –OTiCl3 or –OSiMe3 groups of the other cube corners. The model structures were generated to correspond to experimentally synthesised materials, matching physical properties including density, surface area and accessible volume. It is shown that both methane and carbon dioxide adsorb via physisorption only in the modelled materials. Adsorption isotherms and energies at 300 K for pressures up to 100 bar were generated via molecular simulation. The maximum gravimetric capacity of CH4 is 16.9 wt%, occurring at 300 K and 97 bar. The maximum gravimetric capacity of CO2 is 50.3 wt%, occurring at 300 K and 51.6 bar. The best performing adsorbent was a low-density (high accessible volume) material with no –OTiCl3 groups. The presence of –OTiCl3 did not enhance physisorption even on a volumetric basis, and the high molecular weight of –OTiCl3 groups is a significant penalty on a gravimetric basis. Based on the pair correlation functions, the most favourable adsorption sites for both adsorbates are located in front of the faces of spherosilicate cubes. The self-diffusivity and activation energy for diffusion are also reported. 相似文献
13.
PurposePlanning target volume (PTV) definition based on Mid-Position (Mid-P) strategy typically integrates breathing motion from tumor positions variances along the conventional axes of the DICOM coordinate system. Tumor motion directionality is thus neglected even though it is one of its stable characteristics in time. We therefore propose the directional MidP approach (MidP dir), which allows motion directionality to be incorporated into PTV margins. A second objective consists in assessing the ability of the proposed method to better take care of respiratory motion uncertainty.Methods11 lung tumors from 10 patients with supra-centimetric motion were included. PTV were generated according to the MidP and MidP dir strategies starting from planning 4D CT.ResultsPTVMidP dir volume didn’t differ from the PTVMidP volume: 31351 mm3 IC95% [17242–45459] vs. 31003 mm3 IC95% [ 17347–44659], p = 0.477 respectively. PTVMidP dir morphology was different and appeared more oblong along the main motion axis. The relative difference between 3D and 4D doses was on average 1.09%, p = 0.011 and 0.74%, p = 0.032 improved with directional MidP for D99% and D95%. D2% was not significantly different between both approaches. The improvement in dosimetric coverage fluctuated substantially from one lesion to another and was all the more important as motion showed a large amplitude, some obliquity with respect to conventional axes and small hysteresis.ConclusionsDirectional MidP method allows tumor motion to be taken into account more tightly as a geometrical uncertainty without increasing the irradiation volume. 相似文献
14.
Christian Thaler Tobias Faizy Jan Sedlacik Brigitte Holst Jan-Patrick Stellmann Kim Lea Young Christoph Heesen Jens Fiehler Susanne Siemonsen 《PloS one》2015,10(12)
Background
Magnetic Resonance Imaging (MRI) is an established tool in diagnosing and evaluating disease activity in Multiple Sclerosis (MS). While clinical-radiological correlations are limited in general, hypointense T1 lesions (also known as Black Holes (BH)) have shown some promising results. The definition of BHs is very heterogeneous and depends on subjective visual evaluation.Objective
We aimed to improve clinical-radiological correlations by defining BHs using T1 relaxation time (T1-RT) thresholds to achieve best possible correlation between BH lesion volume and clinical disability.Method
40 patients with mainly relapsing-remitting MS underwent MRI including 3-dimensional fluid attenuated inversion recovery (FLAIR), magnetization-prepared rapid gradient echo (MPRAGE) before and after Gadolinium (GD) injection and double inversion-contrast magnetization-prepared rapid gradient echo (MP2RAGE) sequences. BHs (BHvis) were marked by two raters on native T1-weighted (T1w)-MPRAGE, contrast-enhancing lesions (CE lesions) on T1w-MPRAGE after GD and FLAIR lesions (total-FLAIR lesions) were detected separately. BHvis and total-FLAIR lesion maps were registered to MP2RAGE images, and the mean T1-RT were calculated for all lesion ROIs. Mean T1 values of the cortex (CTX) were calculated for each patient. Subsequently, Spearman rank correlations between clinical scores (Expanded Disability Status Scale and Multiple Sclerosis Functional Composite) and lesion volume were determined for different T1-RT thresholds.Results
Significant differences in T1-RT were obtained between all different lesion types with highest T1 values in visually marked BHs (BHvis: 1453.3±213.4 ms, total-FLAIR lesions: 1394.33±187.38 ms, CTX: 1305.6±35.8 ms; p<0.05). Significant correlations between BHvis/total-FLAIR lesion volume and clinical disability were obtained for a wide range of T1-RT thresholds. The highest correlation for BHvis and total-FLAIR lesion masks were found at T1-RT>1500 ms (Expanded Disability Status Scale vs. lesion volume: rBHvis = 0.442 and rtotal-FLAIR = 0.497, p<0.05; Multiple Sclerosis Functional Composite vs. lesion volume: rBHvis = -0.53 and rtotal-FLAIR = -0.627, p<0.05).Conclusion
Clinical-radiological correlations in MS patients are increased by application of T1-RT thresholds. With the short acquisition time of the MP2RAGE sequences, quantitative T1 maps could be easily established in clinical studies. 相似文献15.
Summary HPLC was combined with a packable microbore guard column to obtain the adsorption isotherm of lysozyme in a Hydrophobic Interaction Chromatography system. The equipment configuration enabled isotherm determination of the protein on a relatively low pressure chromatographic media (TosoHaas 650M Phenyl).Notation Cm,i
is the mobile phase concentration of protein. (M/L3
(liquid))
- Cm,0
=0
- Cs,i
is the stationary phase concentration of protein. It is the concentration of protein on the chromatographic media. (M/L3
(solid))
- Cs,0
=0
- M,L
is the dimensions mass and length
- Vr,i
is the retention volume of the peak front that corresponds to a mobile phase protein on the concentration Cm,i. (L3
(liquid))
- i
i is a counter that is used to keep track of Cm, Cs, and Vr.For example, i=1 in the term Cm,i denotes the first, and lowest, mobile phase protein concentrations are described by higher values of i.
- Vd
is the system dead volume. It consists of all of the system volume that the mobile phase "sees" or contacts, includingchromatographic media interparticle and pore volume. (L3
liquid)
- Vs
the stationary phase volume. Vs is the nonporous bead volume. For porous beads, Vs is the bead volume - the porevolume. (L3
(solid))
- Ve
is the empty column volume. (L3
liquid)
- Vm
is the packed column mobile phase volume and consists of the pore volume and the excluded volume. (L3
(liquid))
- Ve system
is the empty column system volume. (L3
(liquid))
- Vfrit
the volume of mobile phase that fills the column frits. (L3
(liquid))
- Vwoc
the system volume without the column connected. (L3
(liquid)) 相似文献
16.
Ning Zhang Xiaopeng Han Yongchang Liu Xiaofei Hu Qing Zhao Jun Chen 《Liver Transplantation》2015,5(5)
A simple and template‐free method for preparing three‐dimensional (3D) porous γ‐Fe2O3@C nanocomposite is reported using an aerosol spray pyrolysis technology. The nanocomposite contains inner‐connected nanochannels and γ‐Fe2O3 nanoparticles (5 nm) uniformly embedded in a porous carbon matrix. The size of γ‐Fe2O3 nanograins and carbon content can be controlled by the concentration of the precursor solution. The unique structure of the 3D porous γ‐Fe2O3@C nanocomposite offers a synergistic effect to alleviate stress, accommodate large volume change, prevent nanoparticles aggregation, and facilitate the transfer of electrons and electrolyte during prolonged cycling. Consequently, the nanocomposite shows high‐rate capability and long‐term cyclability when applied as an anode material for Na‐ion batteries (SIBs). Due to the simple one‐pot synthesis technique and high electrochemical performance, 3D porous γ‐Fe2O3@C nanocomposites have a great potential as anode materials for rechargeable SIBs. 相似文献
17.
Free‐Standing 3D Nanoporous Duct‐Like and Hierarchical Nanoporous Graphene Films for Micron‐Level Flexible Solid‐State Asymmetric Supercapacitors
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Kaiqiang Qin Enzuo Liu Jiajun Li Jianli Kang Chunsheng Shi Chunnian He Fang He Naiqin Zhao 《Liver Transplantation》2016,6(18)
High energy density and power density within a limited volume of flexible solid‐state supercapacitors are highly desirable for practical applications. Here, free‐standing high‐quality 3D nanoporous duct‐like graphene (3D‐DG) films are fabricated with high flexibility and robustness as the backbones to deposit flower‐like MnO2 nanosheets (3D‐DG@MnO2). The 3D‐DG is the ideal support for the deposition of large amount of active materials because of its large surface area, appropriate pore structure, and negligible volume compared with other kinds of carbon backbones. Moreover, the 3D‐DG preserve the distinctive 2D coherent electronic properties of graphene, in which charge carriers move rapidly with a small resistance through the high‐quality and continuous chemical vapor deposition‐grown graphene building blocks, which results in a high rate performance. Marvelously, ultrathin (≈50 μm) flexible solid‐state asymmetric supercapacitors (ASCs) using 3D‐DG@MnO2 as the positive electrode and 3D hierarchical nanoporous graphene films as the negative electrode display ultrahigh volumetric energy density (28.2 mW h cm?3) and power density (55.7 W cm?3) at 2.0 V. Furthermore, as‐prepared ASCs show high cycle stability clearly demonstrating their broad applications as power supplies in wearable electronic devices. 相似文献
18.
β-Mercaptoethanol interferes in the determination of protein by the Lowry method (1–6). The interference can be overcome by the precipitation of proteins by trichloroacetic acid or acetone or by the use of H2O2 which oxidizes the sulfhydryl groups of β-mercaptoethanol (5). Both these methods have inherent disadvantages. Ross and Schatz (5) described a procedure for protein determination in the presence of high concentrations of β-mercaptoethanol where they removed the interference by the addition of iodoacetate. But addition of iodoacetate decreased the sensitivity of the reaction. The removal of interference by β-mercaptoethanol by heating has also been reported (3), but we observed that this procedure is not feasible when a large amount of β-mercaptoethanol is present in the protein samples. In the method reported in this communication, we made use of vacuum drying for the removal of interference by β-merceptoethanol. This method is simple, sensitive, takes less time, and can be used for the determination of protein in the presence of β-mercaptoethanol at levels as high as 10% in a sample volume of 1.0 ml (1.43 mmol) without using any additional chemical steps. 相似文献
19.
Spirography and pneumotachometry have been used to study airway conductance in apparently healthy high school students aged 15–18 years (120 boys and 120 girls) who were born and reside in Arkhangel’sk. The study was performed in winter. The values of forced expiratory volume during 1 s (FEV1) in the high school students living in the North are 3–22% higher than the reference values and the actual mean volume rates (MVR25–75) are 5–17% lower than the respective reference values in all age and sex groups. The forced expiration time constant at the level of small bronchi is higher than that for medium bronchi. 相似文献
20.
Anterior cruciate ligament (ACL) volume and T21 relaxation times from magnetic resonance (MR) images have been previously shown to predict the structural properties of healing ligaments. We investigated whether MR imaging scan resolution and condition (in vivo, in situ, or ex vivo) affected ACL volume and T21 relaxation times in intact ligaments. ACLs of 14 pigs were imaged using a 3 T scanner and a six-channel flexcoil using at least two of four possible scan conditions: (1) in vivo moderate resolution (n = 14); (2) in vivo high resolution (n = 7); (3) in situ high resolution acquired within 60 minutes of euthanasia (n = 6); and (4) ex vivo high resolution following hind limb disarticulation and one freeze-thaw cycle (n = 7). T21 relaxation times were mapped to the ACL voxels. The total ACL volume was then divided into four sub-volumes (Vol1–4) based on predetermined increasing ranges of T21 times. ACL T21 statistics (first quartile, median, and standard deviation (SD)) were computed. Scan resolution had no effect on the total ACL volume, but Vol1 and first quartile T21 times decreased with high resolution and in situ/ex vivo scan conditions. The most dramatic differences in T21 summary statistics were between in vivo moderate and ex vivo high resolution scan conditions that included a freeze-thaw cycle: ACL T21 SD increased by over 50% in 9 animals, and more than 90% in 4 animals. Our results indicated that T21-based prediction models to quantify in vivo structural properties of healing ligaments should be based on high resolution in vivo MR scan conditions. 相似文献